"If Congressional Republicans refuse to pay America’s bills on time, Social Security checks, veterans benefits will be delayed," Obama said. "... Investors around the world will ask if the United States of America is in fact a safe bet. Markets could go haywire. Interest rates would spike for anyone who borrowed money."

One analyst — Michael Feroli, the chief economist at JP Morgan — speculated what such a situation might look like, specifically if the U.S. missed a payment to bondholders.